JP2015092273A - Optical film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical film that has a small thickness and can exhibit target phase delay characteristics over a wide wavelength range, and a display device, such as a circular polarization plate, and a reflection type LCD, translucent reflection type LCD, or OLED.SOLUTION: There is provided an optical film 100 that includes an optical anisotropic polymer layer 101, and a liquid crystal layer 102 that is present on the polymer layer 101 and has an optical axis in a direction perpendicular to or forming 61.5 degrees with the optical axis of the polymer layer. The optical film 100 further has 1/4 wavelength phase delay characteristics.

Description

  The present invention relates to an optical film, a circularly polarizing plate, and a display device.

  The retardation film can be used in various applications.

  The retardation film can be disposed on one side or both sides of a liquid crystal cell, for example, in order to improve the viewing angle characteristics of an LCD (Liquid Crystal Display). Further, the retardation film is used for reflection prevention and ensuring visibility in a reflective LCD or OLED (Organic Light Emitting Device) (Patent Document 1).

Examples of the retardation film include a retardation film having a ½ wavelength or a ¼ wavelength according to the phase delay characteristics. However, in the conventional retardation film of 1/2 or 1/4 wavelength, the retardation changes for each wavelength, so that the wavelength range that acts on the retardation film of 1/2 or 1/4 wavelength is uniform. There is a problem that is limited only to the sub-range. For example, a film that functions with a ¼ wavelength retardation film for 550 nm wavelength light often does not function with a ¼ wavelength retardation film for 450 nm or 650 nm wavelength light. .
[Prior art documents]
[Patent Literature]
Patent Document 1: Japanese Patent Application Laid-Open No. 8-321381

  Accordingly, the present invention has been proposed to solve the conventional problems as described above, and an object of the present invention is to provide an optical film, a circularly polarizing plate, and a display device.

  The present invention relates to an optical film. An exemplary optical film includes an optically anisotropic polymer layer and a liquid crystal layer present on the polymer layer. In the optical film, the polymer layer and the liquid crystal layer are disposed such that the optical axis of the polymer layer and the optical axis of the liquid crystal layer are perpendicular to each other or approximately 61.5 degrees. In this specification, the term “optical axis” means a slow axis or a fast axis, and unless otherwise specified, means a slow axis. Further, in this specification, the term “vertical, orthogonal, horizontal or parallel” means substantially vertical, orthogonal, horizontal or parallel within a range not damaging the intended effect. Errors within ± 15, ± 10, ± 5 or ± 3 can be included. In the present specification, the angle 61.5 degrees means a substantial 61.5 degrees within a range not damaging the intended effect. Accordingly, the angle may include an error within ± 15, ± 10, ± 5, or ± 3, for example.

  FIG. 1 is a cross-sectional view of an exemplary optical film 100, showing a case where a polymer layer 101 and a liquid crystal layer 102 are included. The optical film 200 can further include, for example, an alignment layer 201 that exists between the polymer layer 101 and the liquid crystal layer 102 as shown in FIG.

  In one example, the optical film may include a film having a quarter wavelength phase retardation characteristic. In this specification, the term “phase delay characteristic of n wavelengths” means a characteristic capable of delaying the phase of incident light by n times the wavelength of the incident light within at least a part of the wavelength range. In one example, the optical film has an in-plane retardation of about 110 nm to 220 nm or about 140 nm to 170 nm with respect to light having a wavelength of 550 nm. In this specification, the term “in-plane retardation of an optical film, polymer layer or liquid crystal layer” is a numerical value calculated by “(nx−ny) × d”, where nx is the optical film, polymer layer. Or the refractive index in the in-plane slow axis direction of the liquid crystal layer, ny is the refractive index in the in-plane fast axis direction of the optical film, polymer layer, or liquid crystal layer, and d is the optical film, polymer layer. Or the thickness of the liquid crystal layer.

  The optical film may have, for example, reverse wavelength dispersion characteristics. For example, the optical film is a film having R (650) / R (550) larger than R (450) / R (550). In the present specification, the symbol “R (X)” means an in-plane retardation of an optical film, a polymer layer, or a liquid crystal layer with respect to light having an “X” nm wavelength. In one example, the optical film has R (450) / R (550) of 0.81 to 0.99, 082 to 0.98, 0.83 to 0.97, 0.84 to 0.96, 0.9. 85 to 0.95, 0.86 to 0.94, 0.87 to 0.93, 0.88 to 0.92 or 0.89 to 0.91, and R (650) / R (550) is 1.01 to 1.19, 1.02 to 1.18, 1.03 to 1.17, 1.04 to 1.16, 1.05 to 1.15, 1.06 to 1.14, 1. 07 to 1.13, 1.08 to 1.12 or 1.09 to 1.11.

  The polymer layer included in the optical film can have, for example, a half wavelength phase delay characteristic. The polymer layer has, for example, an in-plane retardation with respect to light having a wavelength of 550 nm of 200 nm to 290 nm or 220 nm to 270 nm. In the polymer layer, the absolute value of the difference between R (450) / R (550) and R (650) / R (550) is within 5, within 4, within 3, within 2, within 1, within or substantially zero. is there. In one example, the polymer layer has R (450) / R (550) of 0.95 to 1.05 or 0.99 to 1.01, and R (650) / R (550) of 0.95. ~ 1.05 or 0.99 ~ 1.01.

  The polymer layer in the optical film is, for example, a polymer film. For example, a film obtained by stretching a light-transmitting polymer film capable of imparting optical anisotropy by stretching in an appropriate manner can be used in the polymer layer. Moreover, as long as it has optical anisotropy, an unstretched polymer film can also be used with the said polymer layer. In one example, the polymer film has a light transmittance of 70% or more, 80% or more, or 85% or more, and a film manufactured by an absorbent cast method can be used. As the polymer film, a film having a thickness of 3 mm or less, 1 μm to 1 mm, or 5 μm to 500 μm can be used in consideration of the possibility of forming a normally stretched film.

  Examples of the polymer film include a polyolefin film such as a polyethylene film or a polypropylene film, a cyclic olefin polymer (COP) film such as a polynorbornene film, a polyvinyl chloride film, a polyacrylonitrile film, a polysulfone film, a polyacrylate film, and a polyacrylate film. Examples thereof include a cellulose ester polymer film such as a vinyl alcohol film or a TAC (Triacetyl cellulose) film, and a copolymer film of two or more monomers among the monomers forming the polymer. In one example, as the polymer film, a cyclic olefin polymer film can be used. In the cyclic olefin polymer, a ring-opening polymer of a cyclic olefin such as norbornene or a hydrogenated product thereof, an addition polymer of a cyclic olefin, a copolymer of another comonomer such as a cyclic olefin and an α-olefin, or Examples thereof include, but are not limited to, graft polymers in which the polymer or copolymer is modified with an unsaturated carboxylic acid or a derivative thereof.

  The polymer layer is formed in a direction parallel to the longitudinal direction (MD: Mechanical Direction) or the lateral direction (TD: Transverse Direction), or an optical axis formed to form a predetermined angle with the longitudinal direction or the lateral direction. It is a polymer layer which has. In one example, the optical axis of the polymer layer forms 45 degrees or 67.5 degrees with the longitudinal direction or lateral direction of the polymer layer, or any one angle within a range of 45 degrees to 67.5 degrees. Is formed. The angle such as 45 degrees or 67.5 degrees means a substantial 45 degrees or 67.5 degrees within a range not damaging the intended effect, for example, within ± 10, within ± 5, or ± 3. Error can be included.

  For example, if the polymer layer is a stretched polymer film, the optical axis of the polymer layer can be controlled by adjusting the stretch axis in the process of stretching the film.

  The polymer layer may have a thickness of 1 mm or less, 1 μm to 500 μm, for example, about 5 μm to 300 μm, but this can be changed depending on the purpose.

  The liquid crystal layer of the optical film can have a phase delay characteristic of 1/4 wavelength, for example. For example, the liquid crystal layer has an in-plane retardation with respect to light having a wavelength of 550 nm of 95 nm to 145 nm or 105 nm to 120 nm. The liquid crystal layer is a liquid crystal layer in which R (450) / R (550) has a value larger than R (650) / R (550). In one example, the R (450) / R (550) of the liquid crystal layer is 1.01 to 1.19, 1.02 to 1.18, 1.03 to 1.17, 1.04 to 1.16, 1. 05 to 1.15, 1.06 to 1.14, 1.07 to 1.13, or 1.08 to 1.12. R (650) / R (550) is 0.81 to 0.99, It is about 0.82 to 0.98, 0.83 to 0.97, 0.84 to 0.96, 0.85 to 0.95, or 0.86 to 0.94.

  The liquid crystal layer can include, for example, a polymerizable liquid crystal compound. In one example, the liquid crystal layer may include a polymerizable liquid crystal compound in a polymerized form. In this specification, the term “polymerizable liquid crystal compound” means a compound containing a portion capable of exhibiting liquid crystallinity, for example, a mesogen skeleton, and one or more polymerizable functional groups. In addition, “the polymerizable liquid crystal compound is contained in a polymerized form” means that the liquid crystal compound is polymerized to form a skeleton such as a main chain or a side difference of the liquid crystal polymer in the liquid crystal layer. Means the state.

  The liquid crystal layer may contain a polymerizable liquid crystal compound in a non-polymerized state, or may further contain a known additive such as a polymerizable non-liquid crystal compound, a stabilizer, a non-polymerizable non-liquid crystal compound, or an initiator. it can.

  In one example, the polymerizable liquid crystal compound contained in the liquid crystal layer can include a polyfunctional polymerizable liquid crystal compound and a monofunctional polymerizable liquid crystal compound.

  The term “polyfunctional polymerizable liquid crystal compound” means a compound containing two or more polymerizable functional groups among liquid crystal compounds. In one example, the polyfunctional polymerizable liquid crystal compound has 2 to 10 polymerizable functional groups, 2 to 8, 2 to 6, 2 to 5, 2 to 4, 2 to Contains 3 or 2. The term “monofunctional polymerizable liquid crystal compound” means a compound having one polymerizable functional group among liquid crystal compounds.

  When the polyfunctional and monofunctional polymerizable compounds are used together, the phase retardation characteristics of the liquid crystal layer can be effectively adjusted, and the implemented phase retardation characteristics, for example, the optical axis of the phase retardation layer In addition, the phase delay value can be stably maintained.

  In the liquid crystal layer, the monofunctional polymerizable liquid crystal compound is compared with 100 parts by weight of the polyfunctional polymerizable liquid crystal compound, more than 0 parts by weight and 100 parts by weight or less, 1 part by weight to 90 parts by weight, 1 part by weight to 80 parts by weight, From 1 part by weight to 70 parts by weight, 1 part by weight to 60 parts by weight, 1 part by weight to 50 parts by weight, 1 part by weight to 30 parts by weight, or 1 part by weight to 20 parts by weight.

  Within the above range, the mixing effect of the polyfunctional and monofunctional polymerizable liquid crystal compound can be maximized. Unless otherwise specified herein, the unit “parts by weight” means weight percentages.

  In one example, the polyfunctional or monofunctional polymerizable liquid crystal compound is a compound represented by the following Chemical Formula 1.

[Chemical Formula 1]

In Formula 1, A is a single bond, —COO— or —OCO—, and R _{1 to} R ₁₀ are each independently hydrogen, halogen, an alkyl group, an alkoxy group, an alkoxycarbonyl group, a cyano group, A nitro group, —O—Q—P or a substituent of the following chemical formula 2 and two adjacent pairs of R _{1 to} R ₅ or two adjacent groups of R _{6 to} R ₁₀ The pair of substituents are linked to each other to form benzene substituted with —O—Q—P, and at least one of R _{1 to} R ₁₀ is —O—Q—P or the following chemical formula 2 Or at least one pair of the two adjacent substituents of R _{1 to} R ₅ or the two adjacent substituents of R _{6 to} R ₁₀ are connected to each other. Benzene substituted with -OQP is formed. Q is an alkylene group or an alkylidene group, and P is a polymerizable functional group such as an alkenyl group, an epoxy group, a cyano group, a carboxyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, or a methacryloyloxy group.

[Chemical formula 2]

In Formula 2, B is a single bond, —COO— or —OCO—, and R _{11 to} R ₁₅ are each independently hydrogen, halogen, an alkyl group, an alkoxy group, an alkoxycarbonyl group, a cyano group, A pair of two substituents adjacent to each other among R _{11 to} R ₁₅ which are a nitro group or —O—Q—P are linked to each other to form a benzene substituted with —O—Q—P. However, at least one of R _{11 to} R ₁₅ is —O—Q—P or two adjacent pairs of substituents among R _{11 to} R ₁₅ are connected to each other to form —O— Benzene substituted with QP is formed. Q is an alkylene group or an alkylidene group, and P is a polymerizable functional group such as an alkenyl group, an epoxy group, a cyano group, a carboxyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, or a methacryloyloxy group.

  In Formula 1 and Formula 2, two adjacent substituents are connected to each other to form benzene substituted with —O—Q—P, which means that two adjacent substituents are connected to each other. Is formed to form a naphthalene skeleton which is entirely substituted by —O—Q—P.

  In Formula 2, “-” on the left side of B means that B is directly connected to benzene of Formula 1.

  The term “single bond” in Chemical Formula 1 and Chemical Formula 2 means a case where no separate atom exists in the portion represented by A or B. For example, in Formula 1, when A is a single bond, benzene on both sides of A can be directly connected to form a biphenyl structure.

  Examples of the halogen in Formula 1 and Formula 2 include chlorine, bromine, and iodine.

  Unless otherwise specified, the term “alkyl group” in the present specification is, for example, a straight chain having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. Or it means a branched alkyl group, or means, for example, a cycloalkyl group having 3 to 20 carbon atoms, 3 to 16 carbon atoms, or 4 to 12 carbon atoms. The alkyl group can be optionally substituted with one or more substituents.

  In the present specification, the term “alkoxy group” means, for example, an alkoxy group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms unless otherwise specified. means. The alkoxy group is linear, branched or cyclic. The alkoxy group may be optionally substituted with one or more substituents.

  Further, in the present specification, the term “alkylene group” or “alkylidene group” means, for example, an alkylene group or alkylidene group having 1 to 12 carbon atoms, 4 to 10 carbon atoms, or 6 to 9 carbon atoms unless otherwise specified. . The alkylene group or alkylidene group is, for example, linear, branched or cyclic. The alkylene group or alkylidene group may be optionally substituted with one or more substituents.

  In addition, unless otherwise specified, the term “alkenyl group” in the present specification includes, for example, alkenyl having 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, or 2 to 4 carbon atoms. Means group. The alkenyl group is, for example, linear, branched or cyclic. In addition, the alkenyl group can be optionally substituted with one or more substituents.

  In Chemical Formula 1 and Chemical Formula 2, P is, for example, an acryloyl group, a methacryloyl group, an acryloyloxy group, or a methacryloyloxy group, and in another example, is an acryloyloxy group.

  In the present specification, substituents that can be substituted with specific functional groups include alkyl groups, alkoxy groups, alkenyl groups, epoxy groups, oxo groups, oxetanyl groups, thiol groups, cyano groups, carboxyl groups, acryloyl groups, and methacryloyl groups. A group, an acryloyloxy group, a methacryloyloxy group, an aryl group, and the like can be exemplified, but are not limited thereto.

At least one or more of —O—Q—P or a residue of Formula 2 may be present at the position of R ₃ , R _8, or R ₁₃ in Formula 1 and Formula 2. In addition, the substituents constituting the benzene linked to each other and substituted with —O—Q—P are, for example, R ₃ and R ₄ , or R ₁₂ and R ₁₃ . In addition, in the compound of Chemical Formula 1 or the residue of Chemical Formula 2, the substituent other than the residue of —O—Q—P or Chemical Formula 2 or the substituent other than the substituent that is connected to each other to form benzene is: For example, hydrogen, halogen, a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxycarbonyl group containing a linear or branched alkoxy group having 1 to 4 carbon atoms, 4 to 12 carbon atoms A cycloalkyl group, an alkoxy group having 1 to 4 carbon atoms, a cyano group, or a nitro group. In other examples, chlorine, a linear or branched alkyl group having 1 to 4 carbon atoms, and 4 to 4 carbon atoms. 12 cycloalkyl groups, alkoxy groups having 1 to 4 carbon atoms, alkoxycarbonyl groups including linear or branched alkoxy groups having 1 to 4 carbon atoms, or cyano groups.

  The polymerizable liquid crystal compound is contained in the liquid crystal layer in a horizontally aligned state. In one example, the compound is polymerized in a horizontal alignment state and contained in the liquid crystal layer. In this specification, the term “horizontal alignment” means that the optical axis of a liquid crystal layer containing a liquid crystal compound is about 0 to about 25 degrees, about 0 to about 15 degrees, or about 0 to about 10 with respect to the plane of the liquid crystal layer. Means having a tilt angle of about 0 degrees to about 5 degrees or about 0 degrees.

  In one example, the liquid crystal layer has a difference between a refractive index in the in-plane slow axis direction and a refractive index in the in-plane fast axis direction of 0.05 to 0.2, 0.07 to 0.2, 0.09 to 0. 0.2 or 0.1 to 0.2. The refractive index in the in-plane slow axis direction means the refractive index in the direction showing the highest refractive index in the plane of the liquid crystal layer, and the refractive index in the fast axis direction is the lowest in the plane of the liquid crystal layer. It means the refractive index in the direction showing the refractive index. Usually, in a liquid crystal layer having optical anisotropy, a fast axis and a slow axis are formed in directions perpendicular to each other. Each of the refractive indexes is a refractive index measured with respect to light having a wavelength of 550 nm or 589 nm. The difference in refractive index can be measured, for example, according to the manufacturer's manual using Axoscan from Axomatrix.

  The liquid crystal layer has a thickness of about 0.5 μm to 2.0 μm or about 0.5 μm to 1.5 μm.

  The liquid crystal layer having the refractive index relationship and the thickness can implement phase delay characteristics suitable for the intended application.

  As shown in FIG. 2, the exemplary optical film 200 may further include an alignment layer 201 between the polymer layer 101 and the liquid crystal layer 102. The alignment layer is a layer that serves to adjust the optical axis of the liquid crystal layer by aligning the liquid crystal compound in the process of forming the optical film. As the alignment layer, a normal alignment layer known in this field, for example, an alignment layer formed by an imprinting method, a photo alignment layer, a rubbing alignment layer, or the like can be used. The alignment layer has an arbitrary configuration. In some cases, the alignment layer may be imparted without the alignment layer by directly rubbing or stretching the polymer layer.

  The present invention also relates to a method for producing an optical film. The exemplary manufacturing method includes, for example, arranging a liquid crystal layer on an optically anisotropic polymer layer so as to be perpendicular to the optical axis of the polymer layer or to have an optical axis in a direction of about 61.5 degrees. Including a method of forming.

  In one exemplary manufacturing method, the above-described matters can be applied to the specific contents of the polymer layer and the liquid crystal layer.

  The liquid crystal layer is formed by, for example, forming an alignment layer on the polymer layer, forming a coating layer of the liquid crystal composition containing the polymerizable liquid crystal compound described above on the alignment layer, and then aligning the liquid crystal composition. It can manufacture by the method of superposing | polymerizing in the state.

  The alignment layer is, for example, a method in which a polymer film such as polyimide is formed on the polymer layer and subjected to a rubbing process, or a photo-alignment compound is coated and subjected to an alignment process through irradiation of linearly polarized light, or a nano-imprinting system. It can be formed by an imprinting method such as In this field, the intended orientation direction, for example, the orientation direction for forming a liquid crystal layer having an optical axis in a direction perpendicular to the optical axis of the polymer layer or about 61.5 degrees as described above is considered. Various methods for forming the alignment layer are known.

  The coating layer of the liquid crystal composition can be formed, for example, by coating the composition on the alignment layer of the polymer layer by a known method. A liquid crystal layer can be formed by polymerizing after alignment according to the alignment pattern of the alignment layer existing under the coating layer.

  In one example, the manufacturing method can be performed by a method of forming a liquid crystal layer on the polymer layer while transferring the optically anisotropic polymer layer in one direction. In the method, the transport direction of the optically anisotropic polymer layer is such that the optical axis of the polymer layer forms 45 degrees or 67.5 degrees with the transport direction, or any of the range of 45 degrees to 67.5 degrees. It is possible to make one angle.

Referring to FIG. 3, the transfer direction M of the polymer layer 101 forms an angle θ ₁ with the optical axis OP of the polymer layer 101. The θ ₁ is 45 degrees or 67.5 degrees, or any one angle within a range of 45 degrees to 67.5 degrees.

  While the polymer layer 101 is transported in the transport direction M, the liquid crystal layer is formed so that the optical axis OP of the polymer layer 101 and the optical axis OL of the liquid crystal layer are perpendicular to each other or approximately 61.5 degrees. Form. The liquid crystal layer can be formed by the method described above.

  An optical film can be more efficiently manufactured by such a method. In particular, the above-described method makes it possible to efficiently and continuously produce an optical film when linked with an integration step with a linear polarizer described later.

  The present invention also relates to a circularly polarizing plate. An exemplary circularly polarizing plate may include a linear polarizer and the optical film. In one example, the optical film is attached to one surface of the linear polarizer. In the circularly polarizing plate, the light absorption axis of the linear polarizer forms 45 degrees or 67.5 degrees with the optical axis of the polymer layer of the optical film, or any one of 45 degrees to 67.5 degrees. An angle can be formed.

  In one example, in the circularly polarizing plate, for example, the optical axis of the polymer layer of the optical film and the light absorption axis of the linear polarizer may be about 45 degrees or 67.5 degrees. When the optical axis of the polymer layer and the light absorption axis of the linear polarizer form 45 degrees, the optical axis of the polymer layer and the optical axis of the liquid crystal layer can be substantially perpendicular, When the optical axis of the polymer layer and the light collecting axis of the linear polarizer form about 67.5 degrees, the optical axis of the polymer layer and the optical axis of the liquid crystal layer form about 61.5 degrees. Can do.

  FIG. 4 is a diagram illustrating an exemplary circularly polarizing plate 400 in which the optical film 402 is attached to a linear polarizer 401. As shown in FIG. 4, in one exemplary circularly polarizing plate 400, the optical film 402 is included in the circularly polarizing plate 400 such that the polymer layer 101 is positioned closer to the linear polarizer 401 than the liquid crystal layer 102. It is.

  A linear polarizer is a functional element that can extract light oscillating in one direction from incident light oscillating in many directions. As the linear polarizer, for example, an ordinary linear polarizer such as a PVA (poly alcohol) linear polarizer can be used. In one example, the linear polarizer is a polyvinyl alcohol film or sheet having adsorbed and oriented heterochromatic dyes or iodine. The polyvinyl alcohol can be obtained, for example, by gelling polyvinyl acetate. Examples of the polyvinyl acetate include a homopolymer of vinyl acetate; and a copolymer of vinyl acetate and other monomers. Examples of other monomers copolymerized with the vinyl acetate include one or more of unsaturated carboxylic acid compounds, olefin compounds, vinyl ether compounds, unsaturated sulfonic acid compounds, and acrylamide compounds having an ammonium group. can do. The gelation of polyvinyl acetate is generally on the order of about 85 mol% to about 100 mol% or 98 mol% to 100 mol%. The polymerization degree of the polyvinyl alcohol used for the linear polarizer is generally about 1,000 to about 10,000 or about 1,500 to about 5,000.

  In the optical film, the linear polarizer and the liquid crystal layer are attached to each other by an adhesive layer. FIG. 5 exemplarily shows a circularly polarizing plate 500 in which an optical film 402 is attached to a linear polarizer 401 by an adhesive layer 501. For example, the adhesive layer has a glass transition temperature of 36 ° C or higher, 37 ° C or higher, 38 ° C or higher, 39 ° C or higher, 40 ° C or higher, 50 ° C or higher, 60 ° C or higher, 70 ° C or higher, 80 ° C or higher, or 90 ° C. That's it. When an optical film and a linear polarizer are attached with an adhesive layer having the glass transition temperature, an optical film having excellent durability can be formed. Although the upper limit of the glass transition temperature of an adhesive bond layer is not specifically limited, For example, it is about 200 degreeC, about 150 degreeC, or about 120 degreeC.

  The adhesive layer has a thickness of 6 μm or less, 5 μm or less, or 4 μm or less. With such a thickness, the durability of the optical film can be appropriately maintained. The lower limit of the thickness of the adhesive layer is, for example, 0.1 μm, 0.3 μm, or 0.5 μm.

  In one example, the adhesive layer is an active energy ray curable adhesive layer. That is, the adhesive layer can include an adhesive composition cured by irradiation with active energy rays. As used herein, the term “curing of the adhesive composition” means a process of inducing adhesiveness by inducing physical or chemical action and reaction of components contained in the composition. The “active energy ray-curable type” means a type of adhesive or adhesive composition in which the curing is induced by irradiation with active energy rays. The category of the “active energy rays” includes microwaves, infrared rays (IR), ultraviolet rays (UV), X-rays and γ rays, as well as α-particle beams and proton beams. particle beams such as a beam, a neutron beam, and an electron beam, and ultraviolet rays or electron beams can be generally used.

  The adhesive layer can include a radical polymerizable compound or a cationic polymerizable compound. In one example, the radical or cation polymerizable compound is contained in the adhesive layer in a polymerized form. The radical polymerizable compound means a compound that can be polymerized by radical reaction, for example, radical reaction by irradiation of active energy rays, to form an adhesive, and the cationic polymerizable compound is a cation reaction, for example, It means a compound that can be polymerized by a cationic reaction by irradiation of active energy rays to form an adhesive. Each said compound is contained in the adhesive composition, and can form an adhesive agent through the curing reaction of the said composition.

  The adhesive composition may include, for example, only one type of radical polymerizable compound or cationic polymerizable compound, or may include all two types.

  Among cationically polymerizable compounds, epoxy compounds, vinyl ether compounds, oxetane compounds, oxolane compounds, cyclic acetal compounds, cyclic lactone compounds, thirane compounds, thiovinyl ether compounds, spiro ortho ester compounds An ethylenically unsaturated compound, a cyclic ether compound, a cyclic thioether compound or the like can be exemplified, and an epoxy compound can be preferably used.

  Examples of the cation polymerizable epoxy compound include an epoxy resin, an alicyclic epoxy compound, an aliphatic epoxy compound, and an aromatic epoxy compound.

Examples of the epoxy resin include a cresol novolac type epoxy resin and a phenol novolac type epoxy resin. The epoxy resin has a weight average molecular weight ( _Mw: Weight Average Molecular Weight) in the range of 1000 to 5000 or 2000 to 4000. In this specification, the weight average molecular weight means a conversion value with respect to standard polystyrene measured by GPC (Gel Permeation Chromatography), and unless otherwise specified, the term “molecular weight” means “weight average molecular weight”. When the molecular weight is 1000 or more, the durability of the adhesive layer can be appropriately maintained, and when it is 5000 or less, the workability such as the coating property of the composition can be effectively maintained.

  An alicyclic epoxy compound may mean a compound containing one or more alicyclic epoxy groups. The term “alicyclic epoxy group” means a functional group having an aliphatic saturated hydrocarbon ring, and two carbon atoms constituting the ring constituting an epoxy group.

  In the alicyclic epoxy compound, for example, epoxy cyclohexyl methyl epoxy cyclohexane carboxylate compound; epoxy cyclohexane carboxylate compound of alkanediol; epoxy cyclohexyl methyl ester compound of dicarboxylic acid; epoxy cyclohexyl methyl ether compound of polyethylene glycol An epoxy cyclohexyl methyl ether compound of an alkanediol; a diepoxy trispiro compound; a diepoxy monospiro compound; a vinylcyclohexene diepoxide compound; an epoxy cyclopentyl ether compound or a diepoxy tricyclodecane compound; Specifically, 7-oxabicyclo [4,1,0] heptane-3-carboxylate and (7-oxabicyclo [4 1,0] hept-3-yl) methanol; 4-methyl-7-oxabicyclo [4,1,0] heptane-3-carboxylate and (4-methyl-7-oxa-bicyclo [ 4,1,0] hept-3-yl) methanol esterified product; 7-oxabicyclo [4,1,0] heptane-3-carboxylic acid esterified product with 1,2-ethanediol; (7- Oxabicyclo [4,1,0] hept-3-yl) methanol and adipic acid esterified product; (4-methyl-7-oxabicyclo [4,0] hept-3-yl) methanol and adipic acid An esterified product; or an etherified product of (7-oxabicyclo [4,1,0] hept-3-yl) methanol and 1,2-ethanediol can be used.

  In one example, in the alicyclic epoxy compound, as the bifunctional epoxy compound, that is, a compound having two epoxies, a compound in which both of the two epoxy groups are alicyclic epoxy groups can be used. .

  As the aliphatic epoxy compound, an epoxy compound having an aliphatic epoxy group that is not an alicyclic epoxy group can be exemplified. For example, polyglycidyl ether of aliphatic polyhydric alcohol; polyglycidyl ether of alkylene oxide adduct of aliphatic polyhydric alcohol; polyglycidyl ether of polyester polyol of aliphatic polyhydric alcohol and aliphatic polycarboxylic acid; aliphatic Polyglycidyl ethers of polycarboxylic acids; Polyglycidyl ethers of aliphatic polyhydric alcohols and polyester polycarboxylic acids of aliphatic polycarboxylic acids; Dimers, oligomers or polymers obtained by vinyl polymerization of glycidyl acrylate or glycidyl methacrylate; or glycidyl Examples include oligomers or polymers obtained by vinyl polymerization of acrylate or glycidyl methacrylate and other vinyl monomers, such as aliphatic polyhydric alcohols or polymers. Although it is possible to use polyglycidyl ethers of alkylene oxide adducts, but is not limited thereto.

  Examples of the aliphatic polyhydric alcohol include aliphatic polyhydric alcohols having 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, or 2 to 4 carbon atoms. For example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4 -Butanediol, neopentyl glycol, 3-methyl-2,4-pentanediol, 2,4-pentanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2, 4-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 3,5-heptanediol, Aliphatic diols such as 8-octanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol; cyclohexanedimethanol, cyclohexanediol, hydrogenated bisphenol A, hydrogenated bisphenol Examples thereof include alicyclic diols such as F; trimethylolethane, trimethylolpropane, hexitols, pentitols, glycerin, polyglycerin, pentaerythritol, dipentaerythritol, tetramethylolpropane, and the like.

  Moreover, in the said alkylene oxide, C1-C20, C1-C16, C1-C12, C1-C8 or C1-C4 alkylene oxide can be illustrated, for example, ethylene oxide, Propylene oxide or butylene oxide can be used.

  Examples of the aliphatic polycarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, 2-methylsuccinic acid, 2 -Methyladipic acid, 3-methyladipic acid, 3-methylpentanedioic acid, 2-methyloctanedioic acid, 3,8-dimethyldecanedioic acid, 3,7-dimethyldecanedioic acid, 1,20-eicosamethylene Dicarboxylic acid, 1,2-cyclopentanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,4-di Carboxylmethylenecyclohexane, 1,2,3-propanetricarboxylic acid, 1,2,3,4-butanetetracar Phosphate, can be exemplified such as 1,2,3,4-cyclobutane tetracarboxylic acid, but is not limited thereto.

  Aliphatic epoxy compounds do not contain alicyclic epoxy groups, and use of compounds containing 3 or more epoxy groups or 3 epoxy groups is considered in consideration of curability, weather resistance, refractive index characteristics, etc. However, the present invention is not limited to this.

  In the aromatic epoxy compound, as an epoxy compound containing an aromatic group in the molecule, for example, a bisphenol type epoxy resin such as bisphenol A type epoxy, bisphenol F type epoxy, bisphenol S epoxy or brominated bisphenol type epoxy; Examples thereof include novolak type epoxy resins such as epoxy resin or cresol novolac type epoxy resin; cresol epoxy resin or resorcinol glycidyl ether.

  In addition, examples of the cation polymerizable compound include silane compounds having a cation polymerizable functional group. Such a compound can adjust the surface energy of the adhesive and improve the adhesive force, for example. Can be used as a possible ingredient. As the silane compound, for example, a compound represented by the following chemical formula 3 can be used.

[Chemical formula 3]

In Formula 3, R ₁ is a cationic polymerizable functional group bonded to a silicon atom, and R ₂ is a hydrogen, hydroxy group, alkyl group or alkoxy group as a functional group bonded to a silicon atom. And n is a number from 1 to 4.

  Examples of the cationic polymerizable functional group include an alkenyl group such as a vinyl group, a cyclic ether group such as a glycidyl group or an oxetanyl group, a vinyloxy group, the alkenyl group, a cyclic ether group, or a vinyloxy group. A functional group containing can be exemplified.

  In the chemical formula 3, n is preferably 1 or 2.

  In the silane compound, an oligomer type silane compound in which the cation polymerizable functional group is introduced into the molecule of a siloxane oligomer which is a low molecular weight silicone resin whose molecular chain end is blocked with an alkoxysilyl group is used. be able to.

  As the radical polymerizable compound, a compound that has a radical polymerizable functional group such as an acryloyl group or a methacryloyl group and can be polymerized to form an adhesive can be used.

  In one example, the radical polymerizable compound is an acrylamide compound. Examples of the acrylamide radical polymerizable compound include compounds represented by the following chemical formula 4.

[Chemical formula 4]

In Formula 4, R ₁ and R ₂ are each independently hydrogen, an alkyl group, or a hydroxyalkyl group, or R ₁ and R ₂ are connected to form a heterocyclic structure containing nitrogen, and R ₃ is Hydrogen or an alkyl group.

In the present specification, the term “heterocyclic structure” means a cyclic compound containing at least two different atoms as ring constituent atoms, unless otherwise specified. In the case of the chemical formula 4, the heterocyclic structure includes, for example, 3 to 20, 3 to 16, 3 to 12, or 3 including the nitrogen of the chemical formula 1 to which R ₁ and R ₂ are connected. It can contain ˜8 ring atoms. Examples of atoms that can be included in the heterocyclic structure other than the nitrogen include carbon, oxygen, and sulfur. As long as the heterocyclic structure is formed, the chemical formula 4 in which the R ₁ and R ₂ are connected is shown below. In addition to the nitrogen, additional nitrogen atoms can also be included. The heterocyclic structure may not contain an unsaturated bond such as a carbon-carbon double bond, may contain one or more as necessary, and is optionally substituted with one or more substituents. May be.

  Examples of the compound represented by Chemical Formula 4 include (meth) acrylamide, N-alkylacrylamide, N-hydroxyalkyl (meth) acrylamide, and N-acryloylmorpholine, but are not limited thereto.

  Moreover, in a radically polymerizable compound, the compound containing a heterocyclic acetal structure can be illustrated. As used herein, the term “heterocyclic acetal structure” means a heterocyclic structure including a structure in which two oxygen atoms are bonded to one identical carbon atom by a single bond. That is, the compound is, for example, a compound that simultaneously includes a functional group including a heterocyclic acetal structure and the radical polymerizable functional group. The compound can serve as, for example, a diluent for adjusting the viscosity of the composition, and can be used to improve the adhesive force with the liquid crystal layer.

  The heterocyclic acetal structure can contain 4 to 20, 4 to 16, 4 to 12, or 4 to 8 ring atoms, optionally with one or more substituents May be substituted.

  Examples of the heterocyclic acetal structure include structures represented by the following chemical formula 5 or chemical formula 6. Accordingly, the radical polymerizable compound may include a monovalent residue derived from a compound represented by the following chemical formula 5 or 6 together with a radical polymerizable functional group.

[Chemical formula 5]

[Chemical formula 6]

In Formula 5 or 6, R ₄ and R ₅ each independently represent hydrogen or an alkyl group, Q, P, R, and T each independently represent a carbon atom or an oxygen atom, and Q , P, R and T are oxygen atoms, and A and B each independently represent an alkylene group or alkylidene group having 1 to 5 carbon atoms.

  Examples of the radical polymerizable compound containing the heterocyclic acetal structure include compounds represented by the following chemical formula 7.

[Chemical formula 7]

In Formula 7, R ₆ represents hydrogen or an alkyl group, and R ₇ represents a monovalent residue derived from the structure of Formula 5 or 6 or an alkyl group substituted with the monovalent residue. is there.

  In the compound represented by Chemical Formula 7, (2-ethyl-2-methyl-1,3-dioxolan-4-yl) methyl acrylate ((2-ethyl-2-methyl-1,3-dioxolane-4-yl) methylacylate), (2-isobutyl-2-methyl-1,3-dioxolan-4-yl) methyl acrylate ((2-isobutyl-2-methyl-1,3-dioxolane-4-yl) methyl acylate) or (1 , 4-dioxaspiro [4,5] dec-2-yl) methyl acrylate ((1,4-dioxaspiro [4,5] dec-2-yl) methyl acylate) and the like. Is not to be done.

  Moreover, in a radically polymerizable compound, the monomer represented by any one among following Chemical formula 8-Chemical formula 10 can be illustrated.

[Chemical formula 8]

[Chemical formula 9]

[Chemical formula 10]

  In Chemical Formula 8 to Chemical Formula 10, R is hydrogen or an alkyl group, A, B, T, U and W are each independently an alkylene group or an alkylidene group, and Q is an alkyl group or an aryl group. Yes, n is a number from 0 to 5.

  The term “aryl group” as used herein, unless otherwise specified, is a monovalent residue derived from a compound or derivative thereof that includes benzene or a structure in which two or more benzenes are condensed or bonded. Means. The aryl group is, for example, an aryl group having 6 to 22 carbon atoms, preferably 6 to 16 carbon atoms, more preferably 6 to 13 carbon atoms, such as a phenyl group, a phenylethyl group, a phenylpropyl group, Examples thereof include a benzyl group, a tolyl group, a xylyl group, and a naphthyl group.

  In Chemical formula 8, n is a number of 0-3 or 0-2, for example. In the compound of Formula 8, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate , 2-hydroxyethylene glycol (meth) acrylate, 2-hydroxypropylene glycol (meth) acrylate, and the like can be exemplified, but are not limited thereto.

  In Chemical Formula 9, T is, for example, an alkylene group having 1 to 4 carbon atoms. Examples of the compound include β-carboxyethyl (meth) acrylate. In the compound of Chemical Formula 10, Q is an alkyl group having 1 to 4 carbon atoms, and U and W are, for example, each independently an alkylene group having 1 to 4 carbon atoms. Examples of such a compound include 2- (2-ethoxyethoxy) ethyl (meth) acrylate, but are not limited thereto.

  Moreover, in a radically polymerizable compound, the compound represented by following Chemical formula 11 can be illustrated, and such a compound can be used for the improvement of durability of an adhesive agent, for example.

[Chemical formula 11]

  In the chemical formula 11, R is hydrogen or an alkyl group, and P is a monovalent residue derived from an aliphatic saturated hydrocarbon cyclic compound.

  In the above chemical formula 11, the monovalent residue is derived from an aliphatic saturated hydrocarbon cyclic compound, specifically, a compound in which carbon atoms are cyclically bonded, or a compound that is not an aromatic compound or a derivative of the compound. Means a monovalent residue. The aliphatic saturated hydrocarbon cyclic compound is, for example, an aliphatic saturated hydrocarbon cyclic compound having 3 to 20 carbon atoms, 6 to 15 carbon atoms, or 8 to 12 carbon atoms. Such monovalent residues include isobornyl, cyclohexyl, norbornyl, norbornenyl, dicyclopentadienyl, ethynylcyclohexane, ethynylcyclohexene or ethynyldecahydronaphthalene. In one example, an isobornyl group can be used, but is not limited thereto.

  Moreover, in a radically polymerizable compound, an isocyanate functional acrylic ester compound can be used. The compound is not particularly limited as long as it contains an isocyanate group and an acrylic group at the same time. In the above compound, for example, an isocyanate functional aliphatic acrylate ester compound can be used. For example, a compound represented by the following chemical formula 12 can be used.

[Chemical formula 12]

  In the chemical formula 12, R represents hydrogen or an alkyl group, and L represents a divalent hydrocarbon group.

  In the chemical formula 12, as the divalent hydrocarbon group, for example, a divalent aliphatic hydrocarbon group can be used. Specifically, the carbon number is 1 to 20, the carbon number is 1 to 16, the carbon number is 1 to 1. 12, a divalent aliphatic hydrocarbon group having 1 to 8 carbon atoms or 1 to 4 carbon atoms can be used, and the divalent hydrocarbon group is, for example, a linear, branched or cyclic alkylene group or alkynylene. A straight-chain, branched or cyclic alkenylene group; or a straight-chain, branched or cyclic alkynylene group. The hydrocarbon group is, for example, a linear or branched alkylene group or alkynylene group having 1 to 8 carbon atoms.

Examples of the compound include (meth) acryloyloxyalkyl isocyanate, such as (meth) acryloyloxy (C _1-8 ) alkyl isocyanate, (meth) acryloyloxy (C _1-4 ) alkyl isocyanate, or (meth) acryloyloxy. Although ethyl isocyanate can be mentioned, it is not limited to this. The (C _1-8 ) alkyl means a linear, branched or cyclic alkyl having 1, 2, 3, 4, 5, 6, 7 or 8 carbon atoms, and (C _1-4 ) alkyl is Means a straight, branched or cyclic alkyl having 1, 2, 3 or 4 carbon atoms.

  In the isocyanate functional acrylic ester compound, for example, a compound represented by the following chemical formula 13 can be used.

[Chemical formula 13]

  In the chemical formula 13, R represents hydrogen or an alkyl group, and Z represents a tetravalent hydrocarbon group.

  In the tetravalent hydrocarbon group, for example, a tetravalent aliphatic hydrocarbon group can be used. Specifically, the carbon number is 1 to 20, the carbon number is 1 to 16, the carbon number is 1 to 12, and the carbon number is 1. ˜8 or C 1-4 tetravalent aliphatic hydrocarbon groups can be used. For example, a tetravalent hydrocarbon derived from a linear, branched or cyclic alkene; a linear, branched or cyclic alkene; or a linear, branched or cyclic alkyne. Can be included. The hydrocarbon group is, for example, a tetravalent hydrocarbon group derived from a linear or branched alkane having 1 to 8 carbon atoms.

  Examples of the compound include a compound distributed under the name of Laromer LR9000 (manufactured by BASF).

  In addition, as a radically polymerizable compound, a compound having a heterocyclic residue such as tetrahydrofurfuryl (meth) acrylate (tetrahydrofurfuryl (meth) acrylate) or (meth) acryloyl morpholine (meth) acryl morpholine) should be used. Can do.

  In the adhesive, an alicyclic and / or aliphatic epoxy compound as a main component as a cationic polymerizable compound, and an oxetane compound or a silane compound having the cationic polymerizable functional group as a diluent or an additive as necessary A cation curable adhesive composition comprising: a radical curable adhesive composition comprising the acrylamide compound as a main component as a radical polymerizable compound, and optionally containing another radical polymerizable compound as a minor component; As a polymerizable compound, an adhesive composition or a pre-epoxy resin containing a compound represented by any one of Chemical Formula 8 to Chemical Formula 10 as a main component, and optionally containing another radical polymerizable compound, or The mixture of the alicyclic epoxy compound and the aliphatic epoxy compound and the chemical formula 8 to the chemical formula 10 Although the adhesive may be used, including a state where the hybrid curable adhesive composition is cured containing a radically polymerizable compound represented by one or Re, but not limited thereto.

  Selection of each component contained in an adhesive composition and the ratio of each component can be appropriately selected in consideration of the glass transition temperature and the like.

  In addition, the adhesive composition that forms the adhesive may further include a polymerization initiator. As the polymerization initiator, an appropriate type can be selected depending on the components contained in the adhesive composition. For example, a cationic polymerization initiator and / or a radical polymerization initiator can be used.

  In the radical polymerization initiator, for example, an initiator such as benzoin, hydroxyketone compound, aminoketone compound or phosphine oxide compound can be used. For example, a phosphine oxide compound or the like can be used. Specific examples of radical polymerization initiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaninoacetophenone, and 2,2-dimethoxy-2-phenylacetophenone. 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] 2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4′-diethylaminobenzo Enone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethyl Thioxanthone, 2,4-diethylthioxanthone, benzyldimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoate, oligo [2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone] Bis (2,4,6-trimethylbenzoin) -phenyl-phosphine oxide, 2,4,6-trimethylbenzoin-diphenyl-phosphine oxide, and the like, but are not limited thereto. No.

  Further, in the cationic polymerization initiator, for example, as an initiator for releasing a component capable of initiating cationic polymerization by irradiation of active energy rays, an onium salt or an organic metal salt system is used. Examples include ionized cation initiators or non-ionized cation initiators such as organosilanes or latent sulfuric acid systems and other non-ionized compounds.

  In addition, the adhesive composition may include a thermosetting agent, a catalyst, a UV curing agent, a low molecular weight body, a silane coupling agent, a scatterer, an ultraviolet stabilizer, a toning agent, a reinforcing agent, a filler, if necessary. One or more additives such as an antifoaming agent, a surfactant, a photosensitizer, and a plasticizer may be further included.

  In the circularly polarizing plate, the optical film and the linear polarizer may be directly attached through the adhesive layer, and if necessary, between the linear polarizer and the adhesive layer or between the optical film and the adhesive layer. The primer layer may further include a primer layer. For example, in the circularly polarizing plate 500 shown in FIG. 5, the primer layer can be positioned between the linear polarizer 401 and the adhesive layer 501 or between the adhesive layer 501 and the optical film 402. The kind of primer layer is not particularly limited, and any of various kinds generally used for improving adhesiveness can be used.

  Further, the circularly polarizing plate may be provided on one side of the linear polarizer, for example, on the side opposite to the side in contact with the optical film of the linear polarizer, or on the linear polarizer protective layer on both sides of the linear polarizer. May be included.

  Moreover, this invention relates to the manufacturing method of a circularly-polarizing plate. The exemplary manufacturing method may include a method of attaching a linear polarizer and an optical film. In the method, the linear polarizer and the optical film may have an optical absorption axis of the linear polarizer and an optical axis of the polymer layer of the optical film of 45 degrees or 67.5 degrees, or 45 degrees to 67.5 degrees. It can be attached to form any one of the ranges.

  The method for attaching the optical film and the linear polarizer is not particularly limited. For example, the adhesive composition described above is coated on one surface of a linear polarizer or an optical film, and the adhesive composition is cured after laminating the linear modifier and the optical film through the coating layer, or the adhesive A method of laminating a linear polarizer and an optical film by a dropping method using the composition and curing the adhesive composition can be used. Curing of the adhesive composition can be performed by, for example, irradiating an active energy ray with an appropriate intensity with an appropriate amount of light in consideration of components contained in the composition.

  In one example, the manufacturing method of the circularly polarizing plate can be continuously executed by taking over the manufacturing method of the optical film described above. For example, referring to FIG. 3, the polymer layer 101 is unidirectional M, for example, 45 degrees or 67.5 degrees with the optical axis OP of the polymer layer 101, or 45 degrees to 67.5 degrees. An optical film is manufactured by forming a liquid crystal layer on top of the polymer layer 101 while transporting it in a direction that forms any one of the ranges. In the process of forming the liquid crystal layer, the liquid crystal layer can be formed such that the optical axis OP of the liquid crystal layer and the optical axis OP of the polymer layer 101 are substantially perpendicular or approximately 61.5 degrees. .

  A circularly polarizing plate can be manufactured by attaching a linear polarizer while continuously transporting the optical film produced in the above process in the transport direction M. In this process, if the light absorption axis of the linear polarizer is parallel to the transfer direction M of the film, an effective and continuous circularly polarizing plate can be produced.

  When the linear polarizer is attached, for example, when the optical axis of the polymer layer and the optical axis of the liquid crystal layer are perpendicular, the optical absorption axis of the linear polarizer and the optical axis of the polymer layer form about 45 degrees. When the optical axis of the polymer layer and the optical axis of the liquid crystal layer form 61.5 degrees, the light absorption axis of the linear polarizer and the optical axis of the polymer layer are about 67.5. Can be attached to a degree.

  The present invention also relates to a display device. An exemplary display device may include the circularly polarizing plate.

  A specific type of the display device including the circularly polarizing plate is not particularly limited. The device is, for example, an LCD such as a reflective LCD (Liquid Crystal Display) or a transflective LCD, or an OLED (Organic Light Emitting Device).

  In the display device, the arrangement form of the circularly polarizing plates is not particularly limited, and for example, a known form can be adopted. For example, in the reflective LCD, the circularly polarizing plate may be used as any one of the polarizing plates of the LCD panel in order to prevent reflection of external light and ensure visibility. Further, in the OLED, the circularly polarizing plate can be disposed outside the electrode layer of the OLED in order to prevent reflection of external light and ensure visibility.

  The exemplary optical film of the present invention can exhibit a target phase delay characteristic in a wide wavelength range while being relatively thin, for example. In one example, the optical film may exhibit a quarter wavelength phase delay characteristic. The optical film can be manufactured by a simple process. The optical film can be used for an LCD such as a reflective LCD or an OLED, for example.

It is a schematic diagram which shows an example optical film. It is a schematic diagram which shows an example optical film. It is a schematic diagram for demonstrating one exemplary manufacturing method of an optical film. It is a schematic diagram which shows an example circularly-polarizing plate. It is a schematic diagram which shows an example circularly-polarizing plate.

100, 200, 402: Optical film 101: Polymer layer 102: Liquid crystal layer 201: Orientation layer M: Transfer direction OL: Optical axis of liquid crystal layer OP: Optical axis of polymer layer θ ₁ : Optical axis OP of polymer layer the transfer direction M is the angle theta _2: angle between the optical axis OL of an optical axis OP and the liquid crystal layer of the polymer layer 400, 500: circular polarizer 401: linear polarizer 501: adhesive layer

  Hereinafter, although the optical film of this invention is demonstrated in detail with reference to an Example and a comparative example, the scope of the present invention is not limited by the Example shown below.

  In the examples and comparative examples, each physical property was evaluated by the following method.

1. Retardation value The in-plane retardation of the polymer layer, the liquid crystal layer or the optical film was measured by using Axoscan (manufactured by Axomatics), which is a device capable of measuring 16 Muller Matrix. Specifically, 16 muter matrices were obtained by the manufacturer's manual using the equipment, and the phase difference was extracted through this.

2. Polarizance Ellipticity
Polarization Ellipticity is a numerical value indicating the circular polarization efficiency of the optical film or circularly polarizing plate produced in the examples or comparative examples, and can be measured by the manufacturer's manual using Axoscan (manufactured by Axomatics).

  The closer the Polarity Ellipticity value is to 1, the better the circularly polarized light conversion efficiency, and when it is 0, it means linearly polarized light.

Example 1.
A liquid crystal layer having an in-plane retardation of about 105 nm with respect to a wavelength of 550 nm was formed as a polymer layer on a cyclic olefin polymer film having an in-plane retardation of 220 nm with respect to a wavelength of 550 nm by the following method.

  Specifically, the photo-alignment layer forming composition was coated on one surface of the cyclic olefin polymer film so that the thickness after drying was about 1,000 mm, and dried in an oven at 80 ° C. for 2 minutes. In the composition for forming a photo-alignment layer, a mixture of a polynorbornene having a cinnamate group of the following chemical formula A (molecular weight (Mw) = 150,000) and an acrylic monomer is mixed with a photoinitiator (Igacure 907), A composition prepared by dissolving the mixture in a cyclopentanone solvent so that the solid concentration of polynorbornene was 2 wt% was used (polynorbornene: acrylic monomer: photoinitiator = 2: 1). : 0.25 (weight ratio)).

[Chemical Formula A]

Next, the dried composition for forming a photo-alignment film is subjected to an alignment treatment, and aligned so that the optical axis of the liquid crystal layer formed by the alignment layer forms about 61.5 degrees with the optical axis of the cyclic olefin polymer film. The photo-alignment layer was formed by processing. Specifically, a wire grid polarizing plate capable of generating linearly polarized light is positioned on the dried composition in consideration of the position where the optical axis is formed, and the cyclic olefin polymer film is about 3 m / While moving at a speed of min, the alignment treatment was carried out by irradiating the composition for forming a photo-alignment layer with ultraviolet rays (300 mW / cm ² ) for about 30 seconds through the polarizing plate. Next, a liquid crystal layer was formed on the alignment layer subjected to the alignment treatment. Specifically, the liquid crystal composition includes 70 parts by weight of a polyfunctional polymerizable liquid crystal compound represented by the following chemical formula B and 30 parts by weight of a monofunctional polymerizable liquid crystal compound represented by the following chemical formula C, in an appropriate amount A liquid crystal composition containing a photoinitiator was applied to a dry thickness of about 1 μm, and the lower alignment layer was aligned by alignment, and then irradiated with ultraviolet rays (300 mW / cm ² ) for about 10 seconds to crosslink the liquid crystal. And an optical film was produced by forming a liquid crystal layer having an optical axis of about 61.5 degrees with the optical axis of the cyclic olefin film.

[Chemical Formula B]

[Chemical Formula C]

  Next, a conventional polyvinyl alcohol-based linear polarizer was attached to the manufactured optical film to manufacture a circularly polarizing plate. The attachment was performed such that the linear polarizer was attached to the cyclic olefin film. In this process, the optical absorption axis of the linear polarizer and the optical axis of the cyclic olefin film were made to be about 67.5 degrees.

Example 2
An optical film and a circularly polarizing plate are manufactured in the same manner as in Example 1, but the in-plane retardation of the liquid crystal layer with respect to the wavelength of 550 nm is about 135 nm, and the optical axis of the liquid crystal layer and the optical axis of the cyclic olefin polymer film The optical film and the circularly polarizing plate were manufactured so that the optical axis of the cyclic olefin film and the light absorption axis of the linear polarizer were about 45 degrees.

Comparative Example 1
A circular olefin film is manufactured by attaching a cyclic olefin film having an in-plane retardation of about 140 nm with respect to light having a wavelength of 550 nm to a polyvinyl alcohol-based linear polarizer, and the light absorption axis of the linear polarizer and the cyclic olefin film are manufactured. A circularly polarizing plate was manufactured so that the optical axis of the film was about 45 degrees.

Comparative Example 2
A circularly polarizing plate was produced by forming a liquid crystal layer on the polyvinyl alcohol-based linear polarizer in the same manner as in Example 1. In this process, the liquid crystal layer has an in-plane retardation of about 135 nm with respect to light having a wavelength of 550 nm, and the optical axis of the liquid crystal layer and the light absorption axis of the linear polarizer are about 45 degrees, A polarizing plate was produced.

  The physical properties measured for the circularly polarizing plates of the examples and comparative examples are shown in Table 1 below.

Test Example An optical film and a circularly polarizing plate are produced in the same manner as in Example 1. However, the polymer film has an in-plane retardation of about 270 nm with respect to light having a wavelength of 550 nm, and R (450) / R (550) Is a cyclic olefin polymer film in which R (650) / R (550) is 1, and the liquid crystal layer has an in-plane retardation of about 135 nm with respect to light having a wavelength of 550 nm, and R (450) A liquid crystal layer formed using a liquid crystal composition adjusted so that / R (550) was 1.09 and R (650) / R (550) was 0.93 was used. In the optical film or the circularly polarizing plate, the optical axis of the liquid crystal layer and the optical axis of the cyclic olefin polymer film are substantially perpendicular, and the optical axis of the cyclic olefin film and the light absorption axis of the linear polarizer are about 45 degrees. Was made.

  Polarization Ellipticity measured in the same manner as in the examples and comparative examples is about 0.88 for 450 nm light, about 0.94 for 550 nm light, and about 0.94 for 650 nm light. It was about 0.81. Moreover, as a result of evaluating Achromaticity by the same method as the case of an Example and a comparative example, black visual sensation was confirmed.

Claims (18)

  An optically anisotropic polymer layer; and a liquid crystal layer present on the polymer layer and having an optical axis perpendicular to the optical axis of the polymer layer or having a direction of 61.5 degrees. An optical film.   The optical film according to claim 1, which has a phase delay characteristic of ¼ wavelength.   The surface phase retardation for light having a wavelength of 550 nm is 110 nm to 220 nm, and R (650) / R (550) is larger than R (450) / R (550). The optical film as described.   The R (450) / R (550) is 0.81 to 0.99, and the R (650) / R (550) is 1.01 to 1.19. Optical film.   The polymer layer has an in-plane retardation with respect to light having a wavelength of 550 nm of 200 nm to 290 nm, and an absolute value of a difference between R (450) / R (550) and R (650) / R (550) is within 5. The optical film according to claim 1 or 2.   The polymer layer is characterized in that R (450) / R (550) is 0.95 to 1.05 and R (650) / R (550) is 0.95 to 1.05. The optical film according to claim 5.   The polymer layer includes a polyolefin film, a cyclic olefin polymer film, a polyvinyl chloride film, a polyacrylonitrile film, a polysulfone film, a polyacrylate film, a polyvinyl alcohol film, or a cellulose ester-based polymer film, or a single film forming the polymer. The optical film according to any one of claims 1 to 6, comprising a copolymer film of two or more monomers among the monomers.   The polymer layer has an optical axis of 45 degrees or 67.5 degrees with a longitudinal direction or a lateral direction of the polymer layer, or has an angle of 45 to 67.5 degrees. The optical film according to claim 1, wherein the optical film is formed as follows.   The liquid crystal layer has an in-plane retardation with respect to light having a wavelength of 550 nm of 95 nm to 145 nm, and R (450) / R (550) has a value greater than R (650) / R (550). The optical film as described in any one of Claim 1 to 8.   The liquid crystal layer has R (450) / R (550) of 1.01 to 1.19 and R (650) / R (550) of 0.81 to 0.99. Item 10. The optical film according to Item 9.   The liquid crystal layer has a difference between a refractive index in the in-plane slow axis direction and a refractive index in the in-plane fast axis direction, and a thickness of 0.5 μm to 2.0 μm. The optical film according to any one of claims 1 to 10, wherein:   While transporting the optically anisotropic polymer layer in a direction that forms 45 degrees or 67.5 degrees with the optical axis of the polymer layer or forms one angle in the range of 45 degrees to 67.5 degrees. A method for producing an optical film, comprising forming a liquid crystal layer on the polymer layer so as to have an optical axis in a direction perpendicular to the optical axis of the polymer layer or 61.5 degrees.   A circularly polarizing plate comprising: a linear polarizer; and the optical film according to any one of claims 1 to 11 present on one surface of the linear polarizer.   The optical absorption axis of the linear polarizer and the optical axis of the polymer layer of the optical film may be 45 degrees or 67.5 degrees, or any one of 45 degrees to 67.5 degrees. The circularly polarizing plate according to claim 13.   The circularly polarizing plate according to claim 13, further comprising an adhesive layer having a glass transition temperature of 36 ° C. or higher for attaching the linear polarizer and the optical film.   The linear polarizer is attached so that the light absorption axis of the linear polarizer is parallel to the transport direction while continuously transporting the optical film manufactured by the method according to claim 12 in the same direction. A method for producing a circularly polarizing plate.   A display device comprising the circularly polarizing plate according to any one of claims 13 to 15. The display device according to claim 17, wherein the display device is a reflective LCD, a transflective LCD, or an OLED.

Images